Electric control of musical instruments



O 9 E. J. HUGHES 2,765,696

ELECTRIC CONTROL OF MUSICAL INSTRUMENTS Filed Oct. 31. 1950 ELMER J HUGHES INVENTOR.

ATTORNEY 2,765,696 Patented Oct. 9, 1956 ELECTRIC CONTROL OF MUSICAL INSTRUMENTS Elmer J. Hughes, Albany, Califi, assignor of eight percent to Clyde B. Frederick, Albany, Calif.

Application October 31, 1950, Serial No. 193,243

8 Claims. (Cl. 84-4059 This invention relates to musical instruments such as electromagnetically operated xylophones and other instruments responsive to percussive action by electromagnetically actuated mechanisms and the like, and particularly to a control arrangement for such instruments whereby certain unique effects may be produced.

My improvement is particularly adapted for use in Xylophones which are, in turn, employed in conjunction with a piano by a pianist. Instruments of this character as heretofore employed utilized keyboard controlled solenoids and solenoid plungers apertinent to particular tone bars so that a particular tone bar is struck as a particular key is depressed by the musician. If two keys of the keyboard are depressed simultaneously the corresponding tone bars are sounded simultaneously and if the same two keys are depressed by the musician alternately the corresponding tone bars are likewise sounded alternately.

It is one object of my invention to produce alternate soundings of two tone bars while simultaneously depressing two keys.

Another object is to produce repeated and alternating soundings, at audio-perceptible frequencies, of two tone bars so long as'any two keys of the keyboard are held simultaneously depressed.

It is another object to provide an arrangement of circuits and controllers such that the Xylophone may be operated in the normal manner and in the manner referred to herein at the choice of the musician.

Additional objects and advantages will become apparent upon consideration of the following specification wherein reference is made to the accompanying drawings, in which:

Fig. 1 is a wiring diagram showing basic circuits and control devices connected whereby an instrument of the electromagnetically actuated type may be played in the normal manner;

Fig. 2 shows the wiring diagram of Fig. 1 with certain control parts repositioned to enable the musician to attain the new objectives pointed out; and

Fig; 3 shows in side elevation details of two groups of keyboard key operated switches.

In the drawings each of several tone units A, B, C,'. G includes a tone bar 1 actuated by a corresponding solenoid which includes a plunger 3 and a winding 5 under control of a corresponding keyboard key such as A, B, etc. The keys of the keyboard are disposed in actuating relation to respective identical switch groups to which the reference characters 2, 4, 6 and 8 apply, and are shown in the drawing only applied to the group comprised in unit A. Each switch group accordingly comprises the movable contacts 2 and 6 and the stationary contacts 4 and 8.

. Contact. 2 includes a spring and is biased thereby out of contact with contact 4. Contact 6 includes a spring lay-which it is biased to normally contact with stationary contact 4, and out of contact with contact 8. Contacts 2 and 6 are linked by an insulator 10 to move together when the key, as A, is depressed.

Depression of key A causes the two pairs of contacts 2 and 4 and 6 and 8 to close respectively; and the pairs of contacts 4 and 6 to open, as shown in detail for key B in Fig. 3; depression of keys B, C, etc., causes similar closures and openings of the respectively similar contacts of corresponding groups.

In the following description the corresponding contacts and other elements of the several tone units are distinguished by the numeral shown in the drawing combined with the letter of the unit to which that numeral appertains.

The groups of contacts are electrically interlocked in the following manner. The stationary contact A4 is connected by a conductor ab to the movable contact B6. Similarly all other of the corresponding stationary contacts are connected by conductors to corresponding movable contacts in the manner shown so that a series of such contact pairs and conductors normally form a continuous conductor from group A4 to group G6 preferably in the order of the musical scale determined by the respective tone bars with which the keys are associated.

The various stationary contacts A8, B8, etc., are connected to a common conductor or bus 12 and the various movable contacts A2, B2 etc. are respectively connected to one terminal of the windings A5, B5, etc. of the solenoids and the other terminals of the windings 5 are joined to a common conductor 14.

A switch assembly 16 is provided comprising two movable contacts 18 and 20 and a fixed contact 22. Contacts 18 and 20 include springs biasing them to open position as shown in Fig. 2. Contacts 18 and 20 are both caused to electrically connect with contact 22 by a solenoid plunger 24 which normally rests thereon. One of the contacts of one of the tone units, preferably G4, is connected by a conductor 26 and a conductor 28 to one of the movable contacts of switch 16, such as contact 18. Another of the contacts of switch 16, such as contact 22, is connected by a conductor 30, conductors 32 and 34 to one terminal of a source of current 36, which may be the secondary winding of a small transformer the primary winding 38 of which may be connected to a source of alternating current by means of an extension cord and plug not shown. The other terminal of source 36 is normally connected to conductor 14 as will be described.

With the connections as above described, with the contacts of switch 16 closed as shown in Fig. 1, and with all switches of units A, B, etc. in the open and closed positions indicated for group A, the instrument is conditioned for playing in the normal manner, which is: that as each key is depressed, as key G, the corresponding plunger 3 actuated once and the tone bar 1 is struck one blow. To obtain a second blow on tone bar 1 the key G must be released and again depressed. The circuit for energizing the winding G5 extends counterclockwise as shown, from winding 36, conductors 34, 32 and 30, contacts 22, 20, and 18, conductors 28 and 26, contacts G4 and G2, thence through the winding G5 to conductor 14 and thence to the source 36.

As shown in Fig. 1, the depressing of key G has opened the circuit to adjoining conductors gf, fe, etc. which extend from contacts 6 to the contacts 4 of tone units G, F, etc., by moving contact G6 down. No solenoid winding 5 other than G5, or the nearest to G5, to which conductor 26 is connected through contacts 6 and 4 and contacts gf, etc., can be energized from conductors 28 and 26 when key G is depressed. Moreover, assuming key G is not depressed, any other key, as C, when depressed, disables conductors 26 from energizing other solenoids pertinent to keys on its left as shown in the drawing.

Nevertheless, all windings 5 other than the one energized from conductor 26, may be separately or simultaneously energized by depressing their corresponding keys. For this purpose the bus bar 12 is connected by conductors and 42 to contact 20. When any key, as G, is depressed its lower movable contacts, as G6, engages the stationary contact, as G8, connected to bus 12. Accordingly all contacts A4, B4, etc. are either connected. to contact G4 and conductor 26, or to bus 12 irrespective of the positions of any or all other keys. For example, if key B is depressed while key G is depressed, a circuit is established as follows: (counterclockwise) source 36, conductors 34, 32, and 30; contacts 22 and 20; conductors 42, 40, bus bar 12, contacts G8, G6, conductor 8f contacts F4, F6, conductor fe, etc. to contacts B4 and B2, winding B5, conductor 14 and thence to the source 36.

It is believed to be clear from the foregoing that any combination of two or more keys may be operated simultaneously, in alternation, or in sequence, with corresponding tone impulses, with the circuits established through switch 16 as shown in Fig. 1.

Electro-mechanical means are provided for periodically actuating any one or more tone units, as G, selected by the musician by key G. For this purpose a periodically operating switch is provided having a fixed contact 46 joined by conductor 48 to conductor 26. A movable contact 50 is given periodic motion as by motor 52 driving a shaft 54 to which contact 50 is secured for rotation. A slip ring 56 is connected to contact 50, and by a brush 58 to a conductor 60 extending to conductor 34. Assuming the switch contacts 18 and 20 to be in open position of Fig. 2 and the motor 52 to be running, with key G depressed as in Fig. 2, the winding G5 is energized once each time contact 50 engages contact 46. It is evident that, at any simultaneous depression of keys, only one tone bar can be sounded as a result of making the circuit by contacts 50 and 46. Contact 46 is not permitted to energize more than one solenoid at any one time.

While contact 46 is periodically being permitted to energize any one selected solenoid, one or more of the tone bars below it in the tone scale may be selected for periodic energization by means of circuits partially established when the one has been selected. Such circuits include a second contact 62 joined by a conductor 64 to conductor 40. Contact 62 is placed for contact by contactor 50, as it is rotated by motor 52. As shown, the contact 62 is placed so that contact is established by 50 with 62 and 46, successively at equal time intervals. I have found that a shaft speed of approximately four hundred revolutions each minute produces a pleasing eifect.

Suppose for example, that keys G and B are depressed. The circuit for key G has already been traced as energized by rotating contact 50. The circuit for energizing winding B5 extends from source 36, conductors 34 and 60, brush 58, slip ring 56, contacts 50 and 62, conductors 64 and 40, bus 12, contacts G8 and G6, via all intermediate conductors gf cb, and contacts 6 and 4 connected thereby, to contacts B4 and B2 to winding B5. Accordingly, when keys B and G are depressed the corresponding tone bars are sounded alternately, and respectively periodically.

It should be noted that when three keys are depressed, current flows to the corresponding windings 5 over separate circuits from bus bar 12 so that contacts of the groups carry the same value of current irrespective of the number of keys selected.

In the event that any two keys other than G is depressed, such keys as A and C for example, winding C5 is energized from contact 46 over conductors 48, 26, contacts G4 and G6, conductors g), fe, etc. and contacts C4 and C2, the contact G6 being disconnected from bus 12. Winding A5 is energized only from contact 62 over conductors 64, 40, bus 12, contacts C8, and C6 which is disit connected from C4, conductors ab and ba, and contacts A4 and A2.

Of all windings 5 simultaneously selected by depression of keys, only the one nearest in series to connection 26 is energized from contact 46. All others are simultaneously energized from contact 62, which must, accordingly be made larger than contact 46 so as to carry the current possible to be applied thereto. By altering keys depressed from the right to the left side, in the series, of any one depressed key, that key may be caused to sound alone in alternation with all keys to its left, or in unison with all keys to the left of a rightward key which is depressed.

Selection of the alternating effects described above is effected and the motor 52 energized by a knee or foot operated controller 66 which includes a pair of contacts 68 and '76. Controller contact 68 is normally in contact with a stationary terminal 72 of conductor 14. Contact 68 is continuously connected by movable plunger 74 to a brush contact '76 which is joined by a conductor 78 with the source 36. The plunger 74 is movable along brush 76 from the Fig. 1 position, and while brush contact 68 still contacts terminal 72, brush contact 70 with which contact 68 is connected contacts an elongated stationary contact 80. At this connection the following two circuits are established. In one, from source 36 current passes counter-clockwise via conductors 34, 32, 82, winding 84, conductors 86 and 88 to contact through brush contact '76, plunger 74 and brush 76 and thence via conductor 78 to source 36. This circuit raises the plunger 24 and opens the contacts of relay switch 16. A second, or sub-parallel circuit is established via conductors 34, 32, 90, motor 52, conductors 92, and 88, contact 80 and brush 76, conductor 78, causing motor 52 to run. A slight movement, therefore, of controller 66 by the musician causes the keys of the keyboard as selected by the musician for such operation to be energized alternately by the motor operated switch.

In addition to the foregoing effects, the loudness of the response of the tone bars is controlled by controller 66. A resistor 94 placed along the path of contact 68, in the manner of a potentiometer, is inserted in the circuits of windings 5 by forcing plunger 74 farther in the direction of its movement so that its contact passes the contact 72. This decreases the voltage applied to the windings 5 to give the impact force desired without affecting substantially the value of voltage applied to winding 84 and motor 52.

Having thus described my invention and its mode of operation, I claim:

1. In combination with a musical instrument having a series of electrically energized tone units each tone unit having two terminals for its energization and there being keys appertaining individually thereto and a source of electrical energy including terminals for supplying energy to the tone units and substantially identical groups of .switches associated with the respective keys for operation thereby, circuit components for transmitting energy from the source to one terminal of all of the tone units and to terminals of all of the switch groups and from the individual switch groups individually to the other terminals of the individual tone units whereby the energization of the tone units is controlled by the keys through the respective switch groups; said switch groups including electrically interlocked normally closed pairs of contacts, circuit components for connecting a contact of any of the interlocked pairs to a terminal of the source, said switch groups further including two pairs of normally open contacts, one contact of each pair of which form together the first mentioned closed pair of contacts and one of the other contacts of which two pairs is connected to the other terminal of the tone unit and the remaining contact of which two pairs is connected to a second terminal for energization from said source, and means for causing the several pairs of contacts of each group to be changed simultaneously from closed to open positions and simultaneously from open to closed operation of the keys.

2. In combination with a musical instrument having a series of electrically energized tone units each tone unit having two terminals for its energization and there being keys appertaining individually thereto and a source of electrical energy including terminals for supplying energy to the tone units and substantially identical groups of switches associated with the respective keys for operation thereby, circuit components for transmitting ene gy from the source to one terminal of all of the tone units and to terminals of all of the switch groups and from the individual switch groups individually to the other terminals of the individual tone units whereby the energizetion of the tone units is controlled by the keys through the respective switch groups; said switch groups includ ing electrically interlocked normally closed pairs of contacts, circuit components for connecting a contact of one of the interlocked pairs to a terminal of the source, said switch groups further including two pairs of normally open contacts, one contact of each pair of which form the first mentioned closed pair of contacts and one of the other contacts of which two pairs is connected to the other terminal of the tone unit and the remaining contact of which two pairs is connected to a second terminal for energization from said source, and means for causing the several pairs of contacts of each group to be changed simultaneously from closed to open positions and simultaneously from open to closed positions in response to operation of the keys, said circuit components including separate current paths from the source directly to one of the interlocked pairs and from the source to the remaining contact.

3. In combination with a musical instrument having a series of electrically energized tone units each tone unit having two terminals for its energization and there being keys appertaining individually thereto and a source of electrical energy including terminals for supplying energy to the tone units and substantially identical groups of switches associated with the respective keys for operation thereby, circuit components for transmitting energy from the source to one terminal of all of the tone units and to terminals of all of the switch groups and from the individual switch groups individually to the other terminals of the tone units for the energization of the tone units under control of the keys through the respective switch groups, said switch groups including two distinct terminals and the circuit components including two district paths from the source to said two distinct terminals and means for causing current to pass from said two paths through one switch unit and thence to two tone units.

4. In combination with a musical instrument having a series of electrically energized tone units each tone unit having two terminals for its energization and there being positions in response to keys appertaining individually thereto and a source of electrical energy including terminals for supplying energy to the tone units and substantially identical groups of switches associated with the respective keys for operation thereby, circuit components for transmitting energy from the source to one terminal of all of the tone units and to terminals of all of the switch groups and from the individual switch groups individually to the other terminals of the tone units for the energization of the tone units under control by the keys through the respective switch groups, said switch groups being interlocked to provide a series of group contact pairs normally closed to form a continuous path for current extending from switch group to switch group, and the switches of the groups being arranged to receive current from an adjacent group for transmission to the tone unit appertaining thereto and to interrupt the transmission of current from said adjacent group to another adjacent group.

5. In combination with a musical instrument having a series of electrically energized tone units each tone unit having two terminals for its energization and there being keys appertaining individually thereto and a source of electrical energy including terminals for supplying energy to the tone units and substantially identical groups of switches associated with the respective keys for operation thereby, circuit components for transmitting energy from the source to one terminal of all of the tone units and to terminals of all of the switch groups and from the individual switch groups individually to the other terminals of the tone units'for the energization of the tone units under control of the keys through the res ective switch groups, said switch groups including two distinct terminals and the circuit components including wo distinct paths from the source to said two distinct terminals and means for causing current to pass from said paths through one switch unit and thence to two tone units in sequence.

6. In combination with a musical instrument having a series of electrically energized tone units each tone unit having two terminals for its energization and there being keys appertaining individually thereto and a source of electrical energy including terminals for supplying energy to the tone units and substantially identical groups of switches associated with the respective keys for operation thereby, circuit components for transmitting energy from the source to one terminal of all of the tone units and to terminals of all of the switch groups and from the individual switch groups individually to the other terminals of the tone units for the energization of the tone units under control by the keys through the respective switch groups, said switch groups being inter locked to provide a series of group contact pairs normally closed to form a continuous path for current extending from switch group to switch group, and the switches of any one of the groups being arranged when operated to receive current from an adjacent group for transmission to the tone unit appertaining to the one group and to interrupt the transmission of current from said adjacent group to another group, said groups further providing for establishing when operated another energizing circuit to the remaining groups.

7. In combination in a musical instrument having a series of electrically energized tone units, individual key controlled switches and circuit components for energizing and deenergizing said units, mechanical controlling means for energizing a plurality of selected tone units repeatedly and alternately when their keys are operated, and control means operable for rendering the mechanical controlling means effective or inefiective.

8. In combination in a musical instrument having a series of electrically energized tone units, individual key controlled switches and circuit components for energizing and deenergizing said units, mechanical controlling means for energizing two tone units alternately and repeatedly under control of the keys, and control means operable for rendering the mechanical controlling means effective or ineliective.

References Cited in the tile of this patent UNITED STATES PATENTS 

